Conventional building industry practice involves pre-fabricated door frame assemblies which are manufactured at a manufacturing facility, and then transported to a remote location for installation in a building. This door frame assembly includes a door frame and one or more prehung doors. For multiply door assemblies, a storm door and a main or entrance door are provided. The door frame includes a header jamb for the top of the doorway opening and latch and hinge jambs for the sides of the doorway opening in the wall.
With the increase in cost of wood, metal frames, particularly those of steel, have become viable for residential use, as well as for commercial use. Thus, the use of metal door frames is expanding.
The frame should be adaptable to a wide variety of uses. Such uses include the presence or absence of a screen or storm door, in addition to the main door. Further, exterior trim should be provided.
In forming the door frame assembly, the amount of work performed at the factory should be maximized, while the amount of work to be done at the installation site must be minimized. In this way, installation in the field can be accomplished more simply with less experienced labor and more quickly saving time and expense. Further, installation must provide an overall attractive appearance when completed with the building siding and provide a sealed structure to avoid entry of contaminants into the building structure.